1. Field of the Invention
The present invention relates to a structure for ensuring safety of a rotation body (rotor) of a centrifugal separator.
2. Description of the Related Art
In a centrifugal separator, a rotor, which is a body of rotation into which a sample to be separated is put, is rotated at high speed. Therefore, in case of emergency in which the rotor is broken while it is rotating, a high intensity of breaking energy is generated. As a demand for safety with respect to a centrifugal separator used in a laboratory is stipulated in IEC61010-2-0202 which is the international standard, it is demanded that the structure can ensure safety even when half of a rotor is broken when the rotor is rotated at high speed if the worst accident to be estimated happens. Specifically, it is required that pieces of the rotor are confined and a movement of the device is restricted.
As a conventional means for confining this breaking energy, a protector (protective barrier) is provided on the outer circumference of a rotor chamber so as to absorb the breaking energy of a large broken piece of the rotor. In the case of a centrifugal separator in which a living thing sample (e.g. blood) is treated, a cooling pipe for directly cooling the rotor chamber is wound round the outer circumference of the rotor chamber so that the rotor can be cooled. The outer circumference is tightly closed by heat insulating material such as foam material so that the heat radiation and dew condensation can be prevented. The protector is arranged further on the outer circumference. Thickness of the protector and how to arrange the protector in a frame (housing) are designed according to an intensity of the rotary energy of the rotor.
An example of the related art is shown in FIGS. 5, 6 and 7. When an intensity of the breaking energy to be confined is high, it is necessary to increase the thickness of the protector 55. When the protector 55 is sufficiently thick, it is possible to confine the breaking energy by minimizing a deformation of the protector 55. On the other hand, the assemblability of the centrifugal separator is deteriorated and further the weight of the centrifugal separator is increased, which is not appropriate for practical use.
Therefore, in order to absorb the breaking energy, the protector 55 is deformed or rotated when the rotor 57 is broken. In order to deform or rotate the protector 55 when the rotor 57 is broken, that is, in order to move the protector 55, which has been deformed by the pieces of broken rotor 57a, 57b in the frame (housing) 52 in the rotary direction 62 of the rotor and in order to prevent the frame 52 from being deformed by the protector 55 which has been deformed, it is necessary to ensure a fairly large space in the frame between the inner face 52a of the frame and the protector 55 so that the protector 55 does not come into contact with the inner face 52a of the frame even when the protector 55 is deformed by the pieces of the broken rotor 57a, 57b and rotated in the rotary direction 62.
For the above reasons, it is necessary to provide a space in a main body of the centrifugal separator for accommodating a cooling unit and the protector and also to provide a space to allow the protector to be deformed in the main body of the centrifugal separator except for the space in which the rotor chamber is accommodated. Therefore, it is difficult to make the centrifugal separator smaller to save the space. A refrigerating machine to be used as the cooling unit, in which refrigerant is used, is mounted on the centrifugal separator in many cases. Therefore, countermeasures are taken for preventing the electric parts from being affected by a rise in the temperature inside the centrifugal separator caused by the heat generated when the refrigerating machine is operated. For example, a controller section 51 in which the electric parts are mounted is arranged on the side of the rotor chamber separate from the chamber in which the refrigerating machine is arranged. Alternatively, the board, on which the electronic parts are mounted, and the electric parts are arranged in the centrifugal separator main body in a dispersed manner.